Power converter failure detection and prevention

ABSTRACT

A power device includes one or more electrical components, the electrical components including one or more physical attribute. The power device includes one or more sensors configured to monitor the attribute(s). The power device includes a non-transitory computer-readable storage medium including one or more alerting rule. The power device includes one or more processors configured for retrieving the one or more alerting rule from the storage medium. The processors are configured for monitoring one or more sensor value from the sensor(s), wherein the sensor values are associated with the attribute(s). The processors are configured for evaluating the at least one alerting rule during the monitoring, and when the one or more alerting rule results in a pending failure condition, sending a notification to a user.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.16/728,885, filed Dec. 27, 2019, which claims priority to U.S.Provisional Patent Application No. 62/786,596, filed Dec. 31, 2018,which are hereby incorporated by reference in their entireties.

BACKGROUND

Power devices, such as direct current to direct current (DC-DC) powerconverters, direct current to alternating current (DC-AC) powerinverters (one phase, three phase, or the like), and/or the like,comprise multiple electronic components. For example, a 4 kilo-watt (KW)power inverter may comprise up to 5000 electronic components, such ascapacitors, inductors, resistors, relays, transformers, processors,and/or the like. During and after manufacturing of these powerelectronics, the power devices may go through multiple stages of testingto ensure that the power device is fully functional before assembly andshipping to customers. These tests ensure that each device isoperational according to the requirements, specifications, design,and/or the like, and that there are no faulty components.

SUMMARY

The following summary presents a simplified summary of certain features.The summary is not an extensive overview, and is not intended toidentify key or critical elements.

According to the present disclosure, methods and devices for measurementof electrical impedance or temperature changes in electronic componentsare disclosed. Such methods and devices may use one or more sensors(also referred to herein as detectors) such as thermistors, photodiodes,antennas, radio-frequency receivers, microphones, pressure sensors, gassensors, optical sensors, cameras, magnetic field sensors, gaschromatography sensors, transmission line transceivers, and/or the like.The sensors may be located adjacent to or remotely from electroniccomponents, and use secondary transfer or conversion devices, such aselectrical conductors, waveguides (acoustic, optical, electrical,electronic, electromagnetic, and/or the like), fiber optics, mirrors,reflectors, heat sensitive markers, temperature sensitive markers,impedance sensitive markers, thermocouples, and/or the like to transferthe physical parameter values (such as attributes or physical attributesof the components) from the components to the sensors. The impedance ortemperature values may be converted to a secondary physical measurementvalue of improved detectability for recording by a sensor. Systems,assemblies, devices, components, and methods may be provided thatillustrate aspects of selection of the dedicated sensors as well asdetermining the algorithm for converting the measured values toactionable impedance or temperature changes.

As noted above, this Summary is merely a summary of some of the featuresdescribed herein. It is not exhaustive, and it is not to be a limitationon the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood with regard to the followingdescription, claims, and drawings. The present disclosure is illustratedby way of example, and not limited by, the accompanying figures. In thedrawings, like numerals reference similar elements.

FIG. 1A shows schematically a power device with one or more sensors formonitoring multiple components, according to illustrative aspects of thedisclosure.

FIG. 1B shows schematically a power device and PCB regions formonitoring multiple components, according to illustrative aspects of thedisclosure.

FIG. 1C shows schematically a power device or PCB for monitoringmultiple components, according to illustrative aspects of thedisclosure.

FIG. 1D shows schematically processors and sensors for monitoringmultiple components, according to illustrative aspects of thedisclosure.

FIG. 1E shows schematically processors and sensors for a device or PCBglobally, according to illustrative aspects of the disclosure.

FIG. 2 shows schematically a power device with an imaging sensor on acover for monitoring multiple components, according to illustrativeaspects of the disclosure.

FIG. 3 shows schematically a power device with an imaging sensor andmarkers for monitoring multiple components, according to illustrativeaspects of the disclosure.

FIG. 4 shows schematically a power device with an imaging sensor with amirror on a cover for monitoring multiple components, according toillustrative aspects of the disclosure.

FIG. 5 shows schematically a power device with a gas sensor formonitoring multiple components, according to illustrative aspects of thedisclosure.

FIG. 6 shows schematically a power device with an acoustic sensor with acover acting as a sound box for monitoring multiple components,according to illustrative aspects of the disclosure.

FIG. 7 shows schematically a power device with an antenna and receiverfor monitoring multiple components, according to illustrative aspects ofthe disclosure.

FIG. 8 shows schematically a power device with a vibration sensor formonitoring multiple components, and a pressure relief knockout on acover, according to illustrative aspects of the disclosure.

FIG. 9 shows schematically a power device with a transmission linetransceiver for monitoring multiple components, according toillustrative aspects of the disclosure.

FIG. 10 shows schematically a power device with a sensor selection coverfor selecting a component-monitoring sensor, according to illustrativeaspects of the disclosure.

FIG. 11 shows a flowchart of a method for monitoring multiple componentswith a sensor, according to illustrative aspects of the disclosure.

FIG. 12 shows a flowchart of a method for selecting a multiplecomponent-monitoring sensor, according to illustrative aspects of thedisclosure.

FIG. 13 shows a flowchart of a method for inducing component failure andselecting a multiple component-monitoring sensor, according toillustrative aspects of the disclosure.

FIG. 14 shows a flowchart of a method for simulating component failureand selecting a multiple component-monitoring sensor, according toillustrative aspects of the disclosure.

DETAILED DESCRIPTION

The accompanying drawings, which form a part hereof, show examples ofthe disclosure. It is to be understood that the examples shown in thedrawings and/or discussed herein are non-exclusive and that there areother examples of how the disclosure may be practiced.

Failure of a power device may involve the failure of one or morecomponents of the device. The components may fail following a physicalchange which may lead to an impedance change. The altered impedance(such as increased impedance, decreased impedance, and/or the like) orphysical change may result in altered attributes, such as heatproduction, electromagnetic radiation, magnetic field generation, sound,vibration, gas emission, and/or the like. For example, degradation of acomponent may release a gas, such as methane, hydrogen, halogen, and/orthe like. Degradation of a component may release a gas, liquid, or soliddepending on the component and mechanism of failure. These degradationsmay occur at a high temperature, such as between 80 and 600 degreesCelsius (deg C.), for example 125 deg C., 150 deg C., 180 deg C., 250deg C., or the like. Increased heat production may result in increasedtemperatures, which in turn may cause further failures, gas emissions,fire, explosions, and/or the like.

Components within the power device may change over time and use (such as“aging” of the components), as well as change based on the operationalenvironment of the power device. Aging may involve a gradual or abruptchange in impedance of the component, that results in a temperaturechange or other physical attribute or indication, such as noise, EMI,and/or the like. As used herein the terms attribute, physical attribute,property, physical property, parameter, physical parameter (of acomponent) mean a measureable physical change and these terms may beused interchangeably. Some components of the power device may bemonitored during long-term operation, such as using NTC thermistors,sensors, detection circuits, and/or the like. As used herein, the termsensor means sensors, detectors, or other electronic components that mayconvert a physical phenomenon, such as the properties of matter and/orenergy, to an electrical signal indicating the presence/absence of thephenomenon (such as in detection of the phenomenon) or a measurement ofa value representing the phenomenon (such as a sensing of thephenomenon). For example, sensors may be positioned near the componentsthat are likely to fail, that may benefit from monitoring, and/or thelike. For example, a sensor may be adjacent (such as in physicalcontact) to the component, 1 millimeter (mm) from the component, between1 and 10 mm, 1 centimeter from the component (cm), between 1 and 10 cmfrom the component, between 10 and 100 cm from the component, and/or thelike. Alternatively, a sensor is located at least 1 cm, at least 2 cm,or at least 5 cm, from a component. For example, when there is no accessto the location of the highest temperature of a component, such asbetween two adjacent components, a sensor may be placed directly on thecomponent. The monitoring of many components may lead to layoutcomplexity, BOM costs, and/or the like.

Specific historic failures may give indications of which components aremore likely to fail, such as by a statistical analysis of failurerecords. Correlating the failure records to the device testing resultsmay allow correlation of outlier analysis from the testing results tothe failures, and thereby allow tighter testing controls to preventfailures. Furthermore, historic failures may be detectable withdedicated sensors that monitor the components responsible for thefailures. When these sensors indicate a change to the component physicalattributes or properties prior to a failure, an alert may be issued fora service check, the power device may be derated to produce less stresson these components (such as be reducing the current, current changes,voltage, voltage changes, power, and/or the like applied to thecomponent), and/or the like.

Unknown (unpredictable) failures may occur when a component failswithout any history of that component having failed previously. Suchfailures may occur when a component or PCB supplier is changed, a newbatch of components is manufactured and used for the power deviceassembly, when a component manufacturer is changed, when a PCB design(such as a layout) is changed, and/or the like. These unknown failuresmay not be monitored by dedicated sensors that are designed to monitorthese components, and may be detected by general device sensors. Thegeneral device sensors may be located, selected, and/or designed tomonitor all components of the device together. The sensors may be ofmixed types, so that different physical attributes of the unknownfailure may be detected.

For example, a gas emission sensor, an acoustic, a vibration sensor, avisual sensor, an infrared sensor, and/or an EMI sensor may be usedtogether to monitor a power device for unknown failures, and when any ofthe sensor values undergo an abrupt change, then a warning may beissued. When two or more of the sensor values undergo an abrupt change,an alarm may be issued. Different combination of sensors may be selectedto detect as many unknown failures as possible based on the electronics,physics, and components used in the power device. For example, the TDK™InvenSense® MPU-9250 may be used to detect motion, vibration, andmagnetic field changes. Each power device may be more or lesssusceptible to unknown failures depending on the specification, design,components, testing, environment, age, operational history, and/or thelike.

One or more of the sensors listed above may be found during operation,simulation, testing, and/or the like to not provide additionalinformation over the other sensors, and be removed from future productgenerations. For example, a gas sensor may be incorporated into a firstgeneration product, be found to not add additional information over theother products, and removed from the second generation product.

A failing component may affect the physical environment in a variety ofways, sometimes dependent on the failure analysis mode. For example, afilm capacitor that fails due to a ripple current exceeding a thresholdonce every 24 hours may have specific time responses of heat, gasemissions, sounds, vibrations, color changes, and/or the like. A filmcapacitor failing from an over-voltage or dV/dt repeatedly reaching alimiting value may have a different failure response. For example, thefilm capacitor may explode catastrophically or a short circuit may occurwithin the film capacitor and prevent catastrophic failure. Byperforming failure analysis, simulating the failure responses of thephysical attributes/parameters (such as by using a physical parametersimulation tool) and/or inducing failure of the power device (such as bychanging the operation of the component) as a result of the failedcomponents may provide insight into a physical parameter that is a firstsign of a coming failure.

While this first sign may be temperature due to the heat generation ofthe altered impedance component (pre-failure), this first sign may beother measureable senses, such as sound, chemistry, smell, feel, and/orthe like. Once a component or group of components may be identified asbeing failure prone, and the failure mechanisms and timelinesdetermined, the optimal set of sensors/detectors may be selected todetect these failures.

According to the present disclosure, methods and devices for indirectmeasurement of electrical impedance or temperature changes are provided,such as the use of photodiodes, antennas, radio-frequency receivers,microphones, pressure sensors, shock sensors, gas sensors, vibrationsensors, optical sensors, cameras, magnetic field sensors, gaschromatography sensors, transmission line transceivers, and/or the like.The sensors may be located remotely to the components, and use secondarydirection devices, such as electrical conductors, waveguides (acoustic,optical, electrical, electronic, electromagnetic, and/or the like),fiber optics, mirrors, reflectors, heat sensitive markers, temperaturesensitive markers, impedance sensitive markers, thermocouples, and/orthe like to transfer the physical parameter values to thesensors/detectors.

Sensors may be grouped into the corresponding senses, or physicalphenomenon, to measure representative values thereof. For example,sight, or optical sensing, may correspond to visual sensors, infraredsensors, photodetectors, photodiodes, and/or the like. For example,smell/taste, or chemical sensing, may correspond to gas sensors and thelike. For example, touch, or tactile sensing, may correspond tovibration sensors and the like. For example, sound, or auditory sensing,may correspond to acoustic sensors and the like. The selection of thetypes of sensors and the rules/formulas that are used to detect asuspected eminent failure of the components of a power device, ingeneral, may be based on the (1) electronic circuit design of the powerdevice, (2) the electronic components used to produce the power device,and (3) the electronic and physical layout of the electrical and thermalcomponents of the power device.

For example, selection of sensors for detecting component pre-failure ina particular power device may be using optical, chemical, tactile, andauditory sensors. For example, selection of sensors for detectingcomponent pre-failure in a different particular power device may beusing optical, chemical, and tactile sensors. For example, selection ofsensors for detecting component pre-failure in a different particularpower device may be using optical, chemical, and auditory sensors. Forexample, selection of sensors for detecting component pre-failure in adifferent particular power device may be using optical, tactile, andauditory sensors. For example, selection of sensors for detectingcomponent pre-failure in a different particular power device may beusing chemical, tactile, and auditory sensors.

For example, selection of sensors for detecting component pre-failure ina different particular power device may be using optical and chemicalsensors. For example, selection of sensors for detecting componentpre-failure in a different particular power device may be using opticaland auditory sensors. For example, selection of sensors for detectingcomponent pre-failure in a different particular power device may beusing tactile and auditory sensors. For example, selection of sensorsfor detecting component pre-failure in a different particular powerdevice may be using optical sensors. For example, selection of sensorsfor detecting component pre-failure in a different particular powerdevice may be using chemical sensors. For example, selection of sensorsfor detecting component pre-failure in a different particular powerdevice may be using auditory sensors. For example, selection of sensorsfor detecting component pre-failure in a different particular powerdevice may be using tactile sensors.

For example, selection of sensors for detecting component pre-failure ina different particular power device may be using optical, chemical, andtactile sensors. For example, selection of sensors for detectingcomponent pre-failure in a different particular power device may beusing optical, chemical, and auditory sensors. For example, selection ofsensors for detecting component pre-failure in a different particularpower device may be using optical, tactile, and auditory sensors. Forexample, selection of sensors for detecting component pre-failure in adifferent particular power device may be using chemical, tactile, andauditory sensors. In particular, the benefits of each combination ofsensors and the rules/formulas that are used to detect a suspectedeminent failure of the components of a power device may be based on the(1) electronic circuit design of the power device, (2) the electroniccomponents used to produce the power device, and (3) the electronic andphysical layout of the electrical and thermal components of the powerdevice.

The impedance or temperature values may be converted to a secondaryphysical measurement value for detection by a detector or sensor. Forexample, a heat sensitive marker may be used to convert the temperatureto a color change of the marker, and a camera may be used to take adigital image of the marker and use a dedicated image processing methodto convert to a temperature value. For example, an impedance of acomponent may be detected according to a change in voltage or currentduring a test phase of the component, such as when a component ischarged (according to the impedance and an applied voltage), allowed todischarge internally while not operational, and measured after a timehas evolved and the charge reduced due to internal impedance (such asdue to equivalent serial resistance). Systems, assemblies, devices,components, and methods may be provided that illustrate aspects ofselection of the dedicated sensors and detectors as well as determiningthe algorithm for converting the measured values to actionable impedanceor temperature changes. For example, the actionable impedance ortemperature changes may be used to send an alert to a service provider,derate (such as reduce or limit) the instantaneous power rating of thepower device, perform an emergency shutdown, activate an audible alarm,and/or the like.

Electronic components that may fail include, but are not limited to,capacitors, cable connection terminals, inductors, transformers,ferrites, relays, charge bleed-off resistors, fuse holders, wiringinsulation, and/or the like.

Reference is now made to FIG. 1A, which shows schematically a powerdevice 100 with one or more sensors for monitoring multiple components.While power device 100 may use a single reference number (100), it maybe understood that the power device may be a one-off prototype for proofof concept, one of many substantially similar power devices a firstrevision trial production run, one of many substantially similarproduction runs, one of many substantially similar production revisions,and/or the like. Thus the different examples may illustrate aspects ofthese power devices using the single reference 100 to mean one or moreof the disclosed types.

Power device 100 may comprise one or more hardware processors 101, anon-transient storage medium 102, a network interface 110, a userinterface 120, and components configured by a design to convert powerfrom one form to another. The design may be defined by a schematic ofthe electrical connection of components 105 (such as C1, C2, C3, C4, C5,C6, and C7), the components' 105 bill of materials, the sourcedatasheets for components 105, and/or the like. The components may bemonitored by a selection of sensors and/or the like 106. When the lineof sight between sensor(s) 106 and components 105 is obscured orotherwise blocked, a reflecting and/or refracting surface 107 may beused, such as a mirror, waveguide, fiber optic cable, lenses, and/or thelike. Network interface 110 may be connected through a data network 140to other components of a system, such as-remote data loggers 131,machine learning data and analysis components 132, event managercomponents 133, and/or the like. These may be cloud components that arevirtual timesharing of physical resources, remote private resources,remote public resources, and/or the like. The local repository, such asstorage medium 102, may comprise software modules such as a Sensor(s)Monitor 102A, an Event and Risk Calculator 102B, an Event Notifier 102C,and/or the like.

Reference is now made to FIG. 1B, which shows schematically a powerdevice 100 and PCB 116 regions for monitoring multiple components. A PCB116 layout may be composed of different functional regions, eachfunctional region including electrical components needed for differentfunctions of the power device design. For example, regions may includean input terminal region 111, an input regulator and digital processingregion 112, a power converter region 113, a power regulator region 114,an output region 115, where output region 115 may comprise componentsfor output switching, output isolation, output sensing, processing,and/or the like. PCB may have accessible testing pads such as at 117 a-Nwhich represents N testing pads on the PCB layout according to thedesign.

Reference is now made to FIG. 1C, which shows schematically a powerdevice 100 or PCB 116 for monitoring multiple components. In theexample, the input terminal region 111 contains components C111A, C111B,C111C, and C111D, which may be terminal connectors for example. In theexample, the power regulator region 114 contains components C1, C2, C5,and C6, which may be capacitors for example. In the example, the powerconverter region 113 contains components C113A and C4A, which may beswitches for example.

Reference is now made to FIG. 1D, which shows schematically processorsand sensors for monitoring multiple components. Device 100 may comprisea network of sensors and/or detectors for monitoring a physicalcharacteristic of one or more components of FIG. 1C. For example, S1,S2, S5, and S6 monitor C1, C2, C3, and C4 respectively. Processor(s) P1,P2, P3, and P4 may be central processors, such as a 4-core processor,for performing the monitoring and alerting functions, and connected tothe sensors, or a separate hardware processor(s) such as at P5, P6, P7,and P8, may be used to perform local monitoring of the components, suchas at the input terminals, and provide fast response and dedicatedalgorithms for monitoring locally the components, and report themonitoring activities to the main hardware processor(s) as at P1-P4. Inthe example, the power converter region 113 contains sensors S113A andS4A to monitor C113A and C4A respectively. In the example, the inputterminal region 111 contains sensors S111A-D to monitor C111A-D,respectively.

Reference is now made to FIG. 1E, which shows schematically processorsand sensors for a device or PCB globally. Hardware processor(s) P1-P4 ora different processor may be used to monitor sensor values for globalsensors, such as at SG1, SG2, SG4A, and SG5, or a different processorsuch as at P5-P8 used to monitor global sensors such as at SG3. Hardwareprocessor(s) P1-P4 or a different processor may be used to monitorvalues collected from the test pads 117 a-N. The test pads may haveaccess to intermediate electrical parameters, data parameters from thehardware processor(s) P1-P4, and or the like. In the example, the inputterminal region 111 contains sensors S111A-D.

Temperature sensors/detectors, such as thermistors, thermocouples,infrared photodiodes, and/or the like, may be used to directly orindirectly to monitor temperature of components. For example, a thermalIR radiation sensor may be incorporated into the power device, such thatit is located on the PCB, and oriented towards the cover of the powerdevice. The thermal IR radiation sensor may be a single camera unit, anarray of photodiodes with lenses, a single photodiode, and/or the like.The cover may have mirrors and/or waveguides to direct the IR radiationtowards the sensor. When the sensor collects sensor values thatrepresent temperatures, and a processing unit determines that thetemperatures exceed a threshold, an alert may be issued, theinstantaneous power of the power device may be reduced (derated), thepower device may be shut down, and/or the like. A temperature sensor maybe a photodiode that is only sensitive to the wavelengths correspondingto a prohibited temperature, and when a detected value is above athreshold for an amount of time, technicians may be notified and/or thesituation mitigated automatically.

Reference is now made to FIG. 2 , which shows schematically a powerdevice 200 with a sensor 210, such as a temperature sensor, photodiode,thermal camera, digital imaging camera, optical sensor, and/or the like,on a cover 202 for monitoring multiple components 204. Components 204may be located on PCB 203 attached to heat spreader or heat sink 201,and by positioning a sensor 210 at a distance from the components, suchas on cover 202, the largest coverage may be achieved.

For example, Planck's Law may be used to compute the spectral radiationof an ideal black body at a certain temperature. The spectral radiationchanges both peak and minimum wavelength, both of which decrease withincreasing temperature. For example, the peak of a black body at 25degrees Celsius (deg C.) is about 10 micrometers (μm), and the minimumabout 2 μm, while for a black body at 700 deg C. the peak is at about 4μm and the minimum about 0.6 μm. The peak may be computed by Wien'sDisplacement Law: λmax=(2890)/T, where λmax=wavelength of peak energy inmicrons T=temperature in degrees Kelvin. For example, the wavelength forpeak energy emitted from an object at 120 degrees Celsius (120+273=393degrees Kelvin) is: λmax=2890/393K=7.35 μm (at emissivity=1.0). For thetemperature range of 120-190 deg C., the peak irradiance isapproximately between 6.5 and 7 □m. The relative intensity at differenttemperatures and wavelengths may be found by normalizing the intensitiesto the peak intensity at each temperature. The following table providesnormalized intensities at various temperatures and wavelengths(emissivity=1.0).

TABLE 1 fractional intensity at different temperatures (deg C.) □m 120130 140 150 160 170 180 190 0.7 3.6E−16 1.2E−15 3.5E−15 1.0E−14 2.8E−147.2E−14 1.8E−13 4.3E−13 0.8 1.3E−13 3.5E−13 9.0E−13 2.2E−12 5.3E−121.2E−11 2.7E−11 5.6E−11 0.9 1.1E−11 2.7E−11 6.3E−11 1.4E−10 3.0E−106.1E−10 1.2E−09 2.3E−09 1 3.9E−10 8.6E−10 1.8E−09 3.6E−09 7.1E−091.3E−08 2.5E−08 4.4E−08 1.1 6.8E−09 1.4E−08 2.6E−08 5.0E−08 9.0E−081.6E−07 2.7E−07 4.6E−07 1.2 7.0E−08 1.3E−07 2.4E−07 4.2E−07 7.2E−071.2E−06 2.0E−06 3.1E−06 1.3 4.9E−07 8.7E−07 1.5E−06 2.5E−06 4.1E−066.5E−06 1.0E−05 1.5E−05 1.4 2.5E−06 4.3E−06 7.0E−06 1.1E−05 1.7E−052.7E−05 4.0E−05 5.8E−05 1.5 1.0E−05 1.7E−05 2.6E−05 4.0E−05 6.0E−058.9E−05 1.3E−04 1.8E−04 1.6 3.4E−05 5.3E−05 8.1E−05 1.2E−04 1.7E−042.5E−04 3.5E−04 4.8E−04 1.8 2.4E−04 3.5E−04 5.0E−04 7.1E−04 9.7E−041.3E−03 1.8E−03 2.3E−03 2 1.1E−03 1.5E−03 2.1E−03 2.8E−03 3.6E−034.7E−03 6.0E−03 7.6E−03 3 6.4E−02 7.6E−02 9.0E−02 1.1E−01 1.2E−011.4E−01 1.6E−01 1.8E−01 4 3.2E−01 3.6E−01 3.9E−01 4.3E−01 4.6E−015.0E−01 5.3E−01 5.6E−01 5 6.6E−01 6.9E−01 7.3E−01 7.6E−01 8.0E−018.2E−01 8.5E−01 8.8E−01 6 9.0E−01 9.2E−01 9.4E−01 9.6E−01 9.7E−019.8E−01 9.9E−01 1.0E+00 7 9.9E−01 1.0E+00 1.0E+00 1.0E+00 1.0E+009.9E−01 9.8E−01 9.7E−01 8 9.8E−01 9.7E−01 9.6E−01 9.5E−01 9.3E−019.1E−01 8.9E−01 8.8E−01 9 9.1E−01 8.9E−01 8.7E−01 8.5E−01 8.3E−018.0E−01 7.8E−01 7.6E−01 10 8.2E−01 7.9E−01 7.7E−01 7.4E−01 7.1E−016.9E−01 6.6E−01 6.4E−01

The normalized intensities show, for example, that single photon sensorsmay be used for wavelengths up to about 2.5 □m, and above 2.5 □m,photodetectors may detect the intensities associated with differenttemperatures. For example, a First Sensor model AD500-9-TO52-S1avalanche photodiode may be used with an appropriately configureddetection circuit to detect a small number of photons associated withhigh component temperatures, such as above 150 deg C.

Photodetectors may be used below 2.5 □m when sufficient time is allowedfor collecting data. Statistical methods may be used to determine whenthe sensor values represent a temperature signal or noise. For example,an IR photodetector at 1 □m may be used to collect sensor values untilthere is a statistically significant computation that the sensor valuesrepresent the irradiance intensities associated with components above150 deg C., and the power device may be derated to a lower power thatdoes not cause overheating of the components. An alert may be sent to auser to indicate that a component may have reached a high temperature,and subsequently, a technician may be dispatched to the location of thepower device for diagnosis and/or maintenance of the power device.

At higher wavelengths, such as above 3 □m, a photodetector may determinethat a normal operating temperature produces irradiance at the detectedwavelength at a first intensity, and then monitor the intensity duringoperation over time, such as each day at midday, to determine that theintensity does not exceed the first intensity. When the intensityexceeds the first intensity by a certain amount, such as 5-25%, thepower device may take action to prevent failure, including derating,alerting, and/or the like. A test period may be used to determine thefirst intensity, such as by a technician measuring the solar irradianceand estimating a first intensity threshold.

Infrared thermal sensors may be broadband, narrow band, ratio and/or thelike. For example, a broadband thermal sensor may be used at awavelength close to peak wavelength and a high strength signal is usedto detect an over-temperature occurrence. For example, a narrowbandthermal sensor may be used to detect a minimum wavelength exceeding athreshold. For example, a ratio thermal sensor may be used to detect theratio of two narrowband wavelengths to determine that the allowedtemperature has been exceeded. For example, a narrow thermal sensor maybe a Sharp Microelectronics PD410PI2E00F photodetector that has a peakspectral sensitivity at 1 □m corresponding to a possible detection of150-170 deg C. within up to 3 seconds (depending on sensor samplingrate). For example, the detection is near the noise threshold and thenoise is sampled until a temperature is detected. For example, a narrowthermal sensor may be an Osram SFH-3600 phototransistor that may detect150-170 deg C. within up to 0.5 seconds (depending on sensor samplingrate) by passing a current that signals the power device to perform aderating when the spectral density at 1 mm wavelength reaches athreshold. Selection of the photodiode and design of the interruptioncircuit is key to an effective failure monitoring and detection.

Emissivity may also be adjusted to allow better temperature detection.For example, when a selected number of components are to be monitored,the emissivity of these components may be set close to 1.0, and theemissivity of the components that do not need to be monitored may be setclose to 0.0 to reduce the sensor signal from the non-monitoredcomponents.

Other aspects may be incorporated to improve the sensor signal fromoverheating components, such as increasing the percentage field of viewof the components of interest (such as by limiting the detection ofcomponents that are not monitored), modifying sensor materials to bedifferentially sensitive to the critical threshold temperatures (such asa sensor that may amplify detection of components at temperatures of 150deg C.), adjusting sensor sensitivities, and/or the like.

Thermal mapping may be performed using a limited number of thermalsensors at several locations, and converting the pattern of measurementsof the components at these locations to temperature measurements at theother locations where a sensor is not located. For example, area sensors(such as thermal or optical imaging sensors and/or the like) maydetermine patterns of sensor values and when the patterns are disrupted,an indication of impeding failure may be presented and an alertinitiated, and/or the like. For example, a limited number of sensors maybe selected so that sufficient differentiation of a pattern may bedetected.

Thermal imaging may be performed using a thermal camera, similar to alow-cost digital image camera of a smartphone but configured to detectthe infrared radiation associated with increased temperatures. Acombination of sensors may be used that when combined, such as bycomputing a value for each pixel, produce an estimated value for thetemperature of the components seen in the frame. The components that arenot line of sight with the sensor may be monitored using a mirror,waveguide, lens, fiber optic cable, or the like.

Infrared photodiodes may be used to detect particular frequencies ofinfrared radiation, such as IR radiation associated with 150 deg C. Forexample, an InAs/GaAs Quantum Dot Mid-Infrared Photodetector on asilicon substrate may be used to detect 7 micrometer wavelength IRradiation.

In some cases, temperature may be converted to a secondary physicalmeasurement, such as when using a thermo-sensitive marker that changescolor according to temperature. The color may be detected with aninexpensive surface mount camera module. For example, Rohm Semiconductorproduct BH1745NUC-E2 may be used to detect colors of a temperaturemarker or toxic gas marker.

Thermal detection may be performed using one or more photodiodesarranged in a location that allows monitoring the temperature of thecomponents, such as arranged in an array on the inside of the coveropposing the components. By long term monitoring of the photodiodecircuits and converting to temperature estimates, thermal patterns maybe identified that are associated with overheating of the criticalcomponents. For example, the temperature increase may be seen a fewhours in advance of a catastrophic failure. By identifying a possiblefuture failure before it occurs, appropriate changes to the inverteroperation (such as derating) may be initiated and an alert issued toservice the inverter. The inverter may be shut down when catastrophicfailure is eminent, and a warning or notification issued to a serviceprovide to perform maintenance to determine the cause of overheating.

Thermal detection may be performed using a distributed temperaturesensing (DTS) technique, such as an optical time domain reflectometrytechnique, a Raman technique, an optical frequency domain reflectometrytechnique, code correlation DTS, and or the like. In DTS, an optic cableis placed near the components to be monitored and used as a linearsensor. The increased temperature from the components causes thecharacteristics of light transmission in the optical cable to change,such as the lattice oscillations within the solid. Interaction betweenphotons and the oscillating lattice may result in changes to the light,such as Rayleigh scattering and/or the like. The scattering may resultin a frequency shift of the light and other changes. These changes maybe analyzed to determine both the location of the temperature change aswell as the absolute temperature with high accuracy.

By positioning a fiber optic cable throughout the PCB, the temperatureof components near the fiber optic cable may be monitored. A diode lasermay be used to send a photon signal, such as a coded signal, along theoptic cable, and the frequency and spatial scattering measured. Theanalysis of the scattering allows computing of the highest temperaturealong the optic cable, and when the highest temperature exceeds athreshold, steps may be performed to prevent a catastrophic failure ofthe power device.

Visual detection of a possible future failure may be performed by avisual analysis, such as by a color change, a visual change of a heatsensitive marker, and/or the like. For example, a component that isexhibiting excessive heat prior to failure may show a browning or colorchange based on the long term exposure to excessive heat prior tofailure. An imaging sensor, optical sensor, camera, visual sensor,and/or the like may be used to acquire images of the components, andimage analysis performed to detect changes to the components as a resultof the temperature.

Reference is now made to FIG. 3 , which shows schematically a powerdevice 300 with an imaging sensor 310 and markers 305 for monitoringmultiple components 304. Components 304 may be located on PCB 303attached to heat spreader or heat sink 301. Power device 300 may includea cover 302. A camera or imaging sensor 310 may be located at a distanceabove the components, such as in a corner of device 300. A sacrificialcomponent may be used that is easy to monitor but is sensitive to one ormore physical parameter, such as when a lower heat rated component isused. A lower heat rated component may fail when the temperature reaches105 deg C. and the failure may be easily detectable, such as with a lowcost sensor, without a sensor, and/or the like.

For example, Rohm Semiconductor product BH1745NUC-E2 may be used todetect colors heat sensitive markers, component heat discoloration,visible heat of components, and/or the like.

The shape of the components may be monitored using visual analysis ofthe components to detect expansion, leakage, and/or the like.

Reference is now made to FIG. 4 , which shows schematically a powerdevice 400 with an imaging sensor 410 with a mirror 411 on a cover 402for monitoring multiple components 404. Components 404 may be located onPCB 403 attached to heat spreader or heat sink 401. A camera or imagingsensor 410 may be positioned on the PCB, and mirror 411 may reflect thecolor, visual, or infrared radiation from components 404 to the camera410.

Gas emissions may be detected using a dedicated detection to aparticular kind of gas, such as a methane sensor, a hexane sensor, atoluene sensor, a xylene sensor, an ion sensor, a CO sensor, a CO2sensor, and/or the like. For example, prior to a catastrophic failure acomponent may overheat internally, thereby releasing methane vaporassociated with the breakdown of the component's internal isolatingmaterial. For example, the overheating of the component materialproduces carbon monoxide (CO) as a byproduct, and the CO is easilydetectable over the ambient amounts of this gas.

Reference is now made to FIG. 5 , which shows schematically a powerdevice 501 with a gas sensor for monitoring multiple components. Powerdevice 501 may include a cover 502. Gas sensor within device 501 maycomprise a diffusion barrier 503, a separator 504, a sensing electrode505, a counter electrode 506, an electrolyte 507, sensor pins 508,current collectors 509, and/or the like.

For example, a humidity sensor may be used to detect water vapor.

Sound detection of a failure initiation may be associated specificsounds or frequencies, such as vibrations, harmonics, and/or the like,and these may be detected by a microphone, acoustic sensor, pressuresensor, motion sensor, and/or the like. For example, Gaussian mixturemodels (GMM) may be used to isolate the components of certain soundsassociated with the failure or certain components. The power devicesounds may be monitored and analyzed by GMM, and the GMM supervectorsanalyzed to determine when a component failure may be eminent.

Reference is now made to FIG. 6 , which shows schematically a powerdevice 600 with an acoustic sensor 610 with a cover 602 acting as asound box for monitoring multiple components 604. Components 604 may belocated on PCB 603 attached to heat spreader or heat sink 601. Anacoustic sensor 610, such as a microphone, may be positioned on PCB 603to allow easy integration into device 600. Cover 602 may have anacoustic insert 611 that channels, for example, the sounds fromcomponents 604 to a microphone 610.

Acoustic mapping may be performed with multiple microphones, acousticsensors, directional microphones, and/or the like. The data frommultiple sensors with known locations may be converted into maps ofsounds at specific intermediate locations based on the proportionalsignal intensities of the same sounds from different sensors. Thus aspatial map of the sounds source locations may be computed to betterdetect possible failures based on the sounds and known locations of thecomponents. For example, when an acoustic mapping determines that a filmcapacitor is making sounds associated with a ferrite cracking, then itmay be assumed that the acoustic mapping may be erroneous. In similarways, the possible failure associated with certain sounds may beconfirmed or denied based on the acoustic mapping of the source of thesound being in line with then known component locations.

Since the prevention of electromagnetic interference (EMI) is of greatconcern in most electronic products, and or particular concern in powerdevices, the monitoring of EMI may give indication of eminent failuresin components, such as magnetic, inductive, capacitive, or resistivecomponents. When the impedance of one component changes, the balance ofthe components that minimized EMI may be disrupted and the EMI of thedevice may increase dramatically. This increased EMI may be easilydetected using an RF receiver and antenna tuned to the switchingfrequency of the power device, or one of the switching frequencyharmonics.

Reference is now made to FIG. 7 , which shows schematically a powerdevice 700 with an antenna 710B and receiver 710A for monitoringmultiple components 704. Components 704 may be located on PCB 703attached to heat spreader or heat sink 701. The antenna 710B andreceiver 710A may be positioned on PCB 703 to allow easy integrationinto device 700. Cover 702 may have a reflecting insert 711, such as aradio antenna dish, that channels for example the EMI from components704 to sensors 710A and 710B.

A gyroscopic sensor may be used to detect the vibrations of the powerdevice or one of the associated components, such as the PCB, the cover,the heat sink, the terminal detaching devices, and/or the like. Similarto certain sounds, the presence of vibrations at certain frequencies mayindicate that one or more components is failing or is about to fail. Forexample, an arcing condition at one of the terminals of the power devicemay be associated with both sound and vibration.

Reference is now made to FIG. 8 , which shows schematically a powerdevice 800 with a vibration sensor 810 for monitoring multiplecomponents 804, and one or more pressure relief sections 812 on a cover802, such as on the side, top, bottom, back, and/or the like, of thecover. Components 804 may be located on PCB 803 attached to heatspreader or heat sink 801. Vibration sensor 810 may be positioned on PCB803 to allow easy integration into device 800. Cover 802 may have apressure or vibration reflecting insert 811, and a pressure reliefsection 812 of cover 802. When a catastrophic event occurs, the pressurerelief may be configured to allow the pressure generated inside thedevice 800 housing to expand out of the enclosure by pressing againstpressure relief section 812 until the section detaches from cover 802and the pressure is released.

For example, Murata Electronics product number PKGS-25SXAP1-R may beused to detect vibrations, and the vibrations may indicate the physicalresponse of the components to an impedance change, a temperature change,and/or the like. The data recorded by the vibration sensor may beanalyzed by a computer, such as a local processor of the power device, ahome computer, a server, a cloud resource, and/or the like. For example,a GMM applied to the vibration data may be used to compute a supervectorof acoustic parameters, such as a supervector of 5000 parameters, andthe acoustic parameters may be used to identify sounds of componentsexhibiting acoustic behavior identifiable with catastrophic failure,similarly to using supervectors for voice recognition.

Force sensors or strain sensors may be used to detect vibrations, suchas when a strain gauge is connected to a diaphragm, an elongatedmaterial, and/or the like.

Time Domain Reflectometry and Refractometry (TDRR) of the circuit leadsacross/around the components may be used to detect changes in componentimpedance, similarly to the changes in PCB impedance seen with TDR. Theinjection and/or detection points for each TDR may be surroundingspecific components undergoing testing, or distributed around the boardfor TDRR imaging of the circuit. An injection point may be the circuitlocation for electrical connection of a transmitter lead, and adetection point may be a cuit location for electrical connection of areceiver lead.

Reference is now made to FIG. 9 , which shows schematically a powerdevice with a transmission line transceiver 901 for monitoring multiplecomponents, such as a transmission line reflection sensor. The circuitboard 903 acts as a transmission line, and all the impedance changes 904along the electrical path may cause a measureable change in thereflection 905 of the signal energy.

The frequency of the testing during TDRR may be selected from a range offrequencies, or changed dynamically to detect multiple aspects of acomponents impedance (wavelength dependent changes). For example, asweep frequency technique may be used to isolate resonances and/or wavecombinations (such as wave additions or wave cancellations) of thetransmission wavelengths. For example, during a specific board'stesting, a transmission line signature may be detected and recorded, andduring field operation of the board the transmission line signature ismonitored daily for any impedance changes in the circuit.

To use a single transceiver with multiple injection/detection points, aswitching network may be used, such as an FPGA, a dedicated IC, a seriesof relays, and/or the like. For example, an electronic multiplexer suchas the Fairchild 74F138 may be used to switch the transceiver between 8different testing locations of the circuit.

Magnetic field detection may be used to detect changes to the magneticcomponents of a power device, for example, ferrites of inductors,transformers, and of the like. For example, an AK8963 magnetometer fromAsahi Kasei Microdevices Corporation may be used to detect when theferrite of a large inductor has been fractured during operation. When aferrite or magnetic component becomes mechanically compromised, a changein the magnetic field may be detected, such as by the absence of amagnetic field, the appearance of a magnetic field, no change to amagnetic field when one is expected, and/or the like.

When a mapping technique is used, the number of sensors or sensorelements may be determined based on the design and detectable limit ofthe component failure. For example, the number of elements/sensors maydetermine the spatial resolution, temporal resolution, signal to noiseratio, accuracy, detection limit, and/or the like. In some exampledesigns, the temporal resolution and detection limit may be ofimportance in stopping a component failure from causing a catastrophicfailure of the device, minimizing false positive notifications, and/orthe like. In other example applications, the spatial resolution may beof importance to determine the region of the PCB, the location of thefailed components, and/or the like. For example, when a power deviceproduces 500 watts of heat during normal operation, the temperature is102.0 deg C., and when a component fails, 503 watts of heat are producedand the temperature increases to 102.4 deg C. In this example, a 0.4 degC. change needs to be detected so when a confidence of 99% is specifiedin the design, a low noise temperature measurement technique may beneeded to detect this component failure.

When a power device contains a systemic circulation of gas or liquid,the gas or liquid may be monitored at the circulation center, such as apump, fan, and/or the like. For example, the power device is mineral oilcooled and the mineral oil temperature is monitored at the circulatingpump. The systemic circulation may be temporarily halted during themonitoring or testing of the components of the power device toexacerbate the temperature increase of the components that have alteredimpedance.

Other sensors or transducers may be used to detect the effects ofimpedance changes, such as: Color Sensors, Current Transducers, DustSensors, Level Sensors, Flow Sensors, Force Sensors, Gas Sensors,Humidity/Moisture Sensors, Image Sensors, Cameras, Magnetic Sensors,Compass sensors, Magnetic Field sensors, Linear magnetic sensors,Magnetic Position/Proximity/Speed Sensors, Motion Accelerometers, MotionSensors, Gyroscopic sensors, Inertial Measurement Units sensors,Inclinometers, Optical Motion Sensors, Tilt Switches, Vibration Sensors,Optical Sensors, Ambient Light sensors, IR sensors, UV Sensors, DistanceMeasuring sensors, Photo Sensors—CdS Cells, Optical Sensors, ProximitySensors, Shock Sensors, Strain Gauges, Temperature Sensors, NTCThermistors, PTC Thermistors, Resistance Temperature Sensor,Thermocouple, Temperature Probes, Mechanical Thermostats, Solid StateThermostats, Touch Sensors, Ultrasonic sensors, piezo-electric sensors,and/or the like.

Reference is now made to FIG. 11 , which shows a flowchart of a method1100 for monitoring multiple components with a sensor, for exampleutilizing any of the sensors depicted in FIGS. 1D-9 , such as S1, S2,and/or the like. Method 1100 may include a step 1101 of receiving sensordata from any of the sensors disclosed herein, and a step 1102 ofcomputing the physical parameters from the data retrieved from thesensor(s), for example, this and following steps performed usinghardware processor(s) 101 of FIG. 1A. Method 1100 may include a step1103 of comparing the parameters using a rule, an estimate, a formula, athreshold, and/or the like, and a step 1104 of determining an eventmitigation step/rule. Method 1100 may include a step 1105 of recordingthe event, and a step 1106 of update/notification to a user that theevent occurred, such as to allow user to take further actions/steps. Forexample, when a component (such as C1 of FIGS. 1A and 1C) overheats, asensor (such as infrared imaging sensor 410 of FIG. 4 ) may detect thecomponents temperature using mirror 411 on cover 402) detects this andhardware processor(s) 101 (such as located on PCB 403 of FIG. 4 )retrieve the sensor data, compute the temperature, etc. Other sensors asdescribed in FIGS. 1D-9 may be used for the final product powerconverter including cover, while a sensor selection cover described inFIGS. 10 and 12 may be used to determine which sensors and algorithmsmay be used to collect data and issue a notification and/or the likewhen there is a component failure.

To develop accurate detection techniques, physical data may be collectedfrom normal operation, extreme operation, and during failures. Asfailures may be extremely rare, it is not always possible to have allthe data needed to fully differentiate or identify failures before theyhappen. Therefore, devices are needed to collect as much of the data aspossible to determine which of the sensors may best identify the failurebefore it happens. For this purpose, the devices and methods describedmay be used to select the monitoring paradigm that may mitigate the mostrisks associated with failure.

For example, multiple sensors may be incorporated into a sensorselection cover of the power device for detection and monitoring of afew selected power converters, such as a sample of the power converters,while in operation. The data may be analyzed to determine a combinationof sensors and algorithms to incorporate into a power converter for massproduction. In some cases, the determined sensors may be moved from thecover to the PCB for convenience, maintenance, cost, and/or the likeconsiderations. In some cases, a reflector or wave guide type componentmay be attached to the inner side of the cover to divert the emissionsfrom the components to the sensor on the PCB, such as when the sensor onthe PCB does not have line of sight to the components to be monitoredwhile the sensor on the sensor detection cover had line of sight to thecomponents of interest.

Reference is now made to FIG. 10 , which shows schematically a powerdevice 1000 with a sensor selection cover 1002 for selecting acomponent-monitoring sensor. The sensors may be any one or combinationof sensors described herein. Sensor selection cover 1002 may incorporatemany sensors 1010 directed towards components 1004 and PCB 1003. Powerdevice 1000 may be attached to heat separator or heat sink 1001. Thesensor selection cover 1002 may determine, for example, sensor(s) thatmay be sensitive to a physical parameter prior to failure of a component1004. For example, sensor selection cover 1002 may have temperaturesensors, time sensors, humidity sensors, sound sensors, cameras, gassensors, vibration sensors, magnetic sensors, EMI sensors, and/or thelike. Sensor selection cover 1002 may include a control circuit 1011,including a power supply, a battery backup, a communication interface,and/or the like. Sensor selection cover 1002 may include a powerconnector 1012 to power device 1000 (for receiving electrical power forthe cover from device 1000), and/or the like.

For example, sensor selection cover 1002 may have a control circuit 1011including a communication interface, such as a network interface, aWi-Fi™ interface, a cellular network data interface, and/or the like.Sensor selection cover 1002 control circuit 1011 may include one or morehardware processors, with connected non-volatile, computer-readablestorage medium there attached, and the one or more hardware processorsare configured to receive data from the sensors, and record the sensordata to the storage medium. In this manner, sensor selection cover 1002may collect sensor data from components under a variety of operatingconditions, and in some circumstances collect data from a failure event,and/or the like. Such data may then be analyzed to determine thesensors, rules, thresholds, and/or the like, for example, as used inmethod 1100 of FIG. 11 of comparing the parameters using a rule, anestimate, a formula, a threshold, and/or the like. For example, sensorselection covers 1002 may be incorporated at power generationinstallations located at a variety of environmental conditions. Forexample, the sensor selection covers 1002 may replace power devicecovers that do not incorporate sensors 1010 at locations that havespecific ambient temperature, humidity, barometric pressure, irradiance,and/or the like, such as high ambient humidity, high temperature, normalbarometric pressure, low barometric pressure, high irradiance, and/ordifferent combinations to cover a range of ambient conditions.Collecting the sensor data in these conditions, possibly combined withsimulation data of failures, may allow determining whichsensors/algorithms best differentiate between components that fail andthose that don't.

Sensor selection covers 1002 may be located at specific power generationsystem sites, when power devices 1000 may be in use, and collect datafrom these components 1004. When enough data has been collected tocharacterize the operating environment and normal sensor readings ofpower device components 1004, a simulation, induction, and/or failureanalysis may be used to determine which of the sensors may be mostsensitive to the failure of a specific component, of failure or each ofthe components considered one by one to determine which of the sensorsmay be most sensitive to an unknown failure. For example, beta sites maybe selected for monitoring solar inverters, and the beta sites may beconfigured with a sensor selection cover on the inverter to monitor thesensor readings of the inverters during normal operation.

Monitoring with a sensor selection cover may benefit when the sensorsare not part of a power device printed circuit board (PCB), but on aseparate part, such as a cover, a base, or the like. For example, thecover may be a self-contained sensor selection cover which mayincorporate a power supply, a communication interface, a backup power,and/or the like.

The test pads for the PCB and component testing may be utilized formonitoring of PCB component impedance. For example, a sensor selectioncover may have probes electrically connected to the test pads of the PCBand the sensor selection cover records the electrical data from thesepads during operation of the power device.

Sensor selection cover may have independent power supplies, batterybackup power supplies, communication interfaces, processors, and/or thelike, where the components of the sensor selection cover are independentfrom the components of the inverter, and may monitor the physical andelectrical properties of the power device during operation and/orfailure.

A sensor selection cover may be used to select suitable sensors forincorporating in a power device for failure monitoring of the powerdevice and/or components. Sensor selection cover may include multiplesensors of various types and have data logging capabilities. These mayalso include logging direct measurements of the components using one setof sensors, as well as indirect measurements such as redirected physicalproperties to sensors using mirrors, acoustic channels, waveguides,transforming materials, and/or the like.

Reference is now made to FIG. 12 , which shows an exemplary flowchart ofa method 1200 for selecting a multiple component-monitoring sensor.Method 1200 includes a step 1201 of attaching a sensor selection coverto a multiple power device of the same design (such as power deviceswith similar layout, components, and/or the like). For example,referring to FIG. 10 , smart cover 1002 may incorporate many sensors1010 directed towards components 1004 and PCB 1003 attached to heatseparator or heat sink 1001. The sensor selection cover may determine,for example, sensor(s) that may be sensitive to a physical parameterprior to failure of a component 1004. For example, sensor selectioncover 1002 may have temperature sensors, time sensors, humidity sensors,sound sensors, cameras, gas sensors, vibration sensors, magneticsensors, EMI sensors, and/or the like. Sensor selection cover 1002 mayhave a power supply, a battery backup 1011, a power connector 1012 tothe power device (for receiving power for the cover from the device),and/or the like.

Method 1200 includes a step 1202 of collecting sensor data from thepower device during normal operation. For example, in FIG. 10 , sensorselection cover 1002 may have a communication interface 1011, such as anetwork interface, a Wi-Fi™ interface, a cellular network datainterface, and/or the like. Smart cover 1002 may have control circuit1011 including one or more hardware processors, with connectednon-volatile, computer-readable storage medium there attached, and theone or more hardware processors are configured to receive data from thesensors, and record the sensor data to the storage medium. Smart cover1002 may collect sensor data from components under normal operatingconditions. Method 1200 includes a step 1203 of computing normaloperating ranges of sensors based on the data collected during normaloperations. Method 1200 includes a step 1204 of placing the units inselected environmental conditions, such as high humidity environments,or attaching covers to power devices located in extreme environments,such as extremely high or low temperature environments. Method 1200includes a step 1205 of collecting sensor data from the power deviceduring operation in the selected environments. For example, in FIG. 10 ,smart cover 1002 may collect sensor data from components under selectedoperating conditions. Method 1200 includes a step 1206 of computing arule/formula for differentiating the component operation in differentconditions based on the sensor data, and a step 1207 of selecting one ormore detectors/sensors that for the power device design.

For example, step-wise linear regression, principle component analysis,multivariate statistics, and/or the like, of the sensors' measurementsof the components and simulations data may be used find the sensorsmeasurements and formulas/rules that differentiate between normaloperation of the components and failure of the components. The sensorsmeasure the components physical parameters, which may be surrogates ofthe electrical parameters related to the reliability of the components.For example, temperature may be related to the ESR of the component.

A power device cover or sensor selection cover may include pressurerelief breakout regions in the cover, out-gassing relief paths, and/orthe like.

Once the normal operating physical parameters and characteristics aredetermined, the Gaussian distributions for normal and extreme operationof the components may be determined. A power device with a sensorselection cover may be configured and operated to induce failure of oneor more components, such as by introducing humidity, heat, temperaturechange, voltages, currents, and/or the like. Equivalent serialresistance (ESR) may be measured in laboratory conditions, as well asthe sensor values. The ESR and sensor values may be monitored untilfailure, and the results analyzed to determine which sensor detected theESR changes, may be correlated with the ESR changes, was statisticallyanalyzed to determine the ESR changes (such as using multivariateanalysis), and/or the like.

For example, the types of physical parameters or the sensors used todetect the physical parameters may be: Gas Chromatography, Sound,Vibration, Light, EMI, and/or the like.

Laboratory tests of components during induced failures may detect thephysical parameters associated with the component failure, and byrepeating these failure inductions, enough data may be collected todetermine a threshold for detection, such as a 95% confidence intervalthreshold and/or the like. Together with rules and/or combinations ofsensor/detector values, the parameters and algorithms that may detectfailure of components may be determined based on normal, extreme, andfailure detections (such as using machine learning, multivariatestatistics, outlier analysis, and/or the like). The laboratory test maybe performed in a laboratory using mock up power devices, powergeneration components/elements/systems, and/or the like, or in the field(such as a working power generation installation) using the realcomponents/devices. In field-induced failures, additional devices and/orprecautions may be incorporated to prevent harm or permanent damage fromthe induced failures.

The analysis may be used to select the incorporation of sensors in thepower device, such as to achieve a specific confidence interval, a falsepositive rate, a receiver-operator curve value, and/or the like.Monitoring of these selected sensors using algorithms for failuredetection and/or the like may allow detection of a component that isabout to fail.

Reference is now made to FIG. 13 , which shows an exemplary flowchart ofa method 1300 for inducing component failure and selecting a multiplecomponent-monitoring sensor. Method 1300 may include a step 1301 ofattaching a sensor selection cover to one or more power device. Forexample, referring to FIG. 10 , smart cover 1002 may incorporate manysensors 1010 directed towards components 1004 and PCB 1003 attached toheat separator or heat sink 1001. The sensor selection cover maydetermine, for example, sensor(s) that may be sensitive to a physicalparameter prior to failure of a component 1004. For example, sensorselection cover 1002 may have temperature sensors, time sensors,humidity sensors, sound sensors, cameras, gas sensors, vibrationsensors, magnetic sensors, EMI sensors, and/or the like. Sensorselection cover 1002 may have a power supply, a battery backup 1011, apower connector 1012 to the power device (for receiving power for thecover from the device), and/or the like.

Method 1300 may include a step 1302 of collecting sensor data from thepower device. For example, in FIG. 10 , sensor selection cover 1002 mayhave a communication interface 1011, such as a network interface, aWi-Fi™ interface, a cellular network data interface, and/or the like.Smart cover 1002 may have one or more hardware processors, withconnected non-volatile, computer-readable storage medium there attached,and the one or more hardware processors are configured to receive datafrom the sensors, and record the sensor data to the storage medium.Smart cover 1002 may collect sensor data from components under normaloperating conditions. Method 1300 may include a step 1303 of computingnormal operating ranges of sensor values based on the data collectedduring normal operations. Method 1300 may include a step 1304 inducingcomponent failure, such as by changing a temperature, a humidity, anelectrical voltage, an electrical current, and/or the like. Method 1300may include a step 1305 of collecting one or more sensors' data duringthe failure of the component. For example, in FIG. 10 , smart cover 1002may collect sensor data from components from a failure event, and/or thelike. Method 1300 may include a step 1306 of computing a rule/formula ofone or more sensor values to detect the failure. Method 1300 may includea step 1307 of selecting detectors/sensors for the power device design.

Reference is now made to FIG. 14 , which shows an exemplary flowchart ofa method 1400 for failure analysis/simulating component failure andselecting a multiple component-monitoring detector. Method 1400 mayinclude a step 1401 of attaching a sensor selection cover to one or morepower device. For example, referring to FIG. 10 , smart cover 1002 mayincorporate many sensors 1010 directed towards components 1004 and PCB1003 attached to heat separator or heat sink 1001. The sensor selectioncover may determine, for example, sensor(s) that may be sensitive to aphysical parameter prior to failure of a component 1004. For example,sensor selection cover 1002 may have temperature sensors, time sensors,humidity sensors, sound sensors, cameras, gas sensors, vibrationsensors, magnetic sensors, EMI sensors, and/or the like. Sensorselection cover 1002 may have a power supply, a battery backup 1011, apower connector 1012 to the power device (for receiving power for thecover from the device), and/or the like.

Method 1400 may include a step 1402 of collecting sensor data from thepower device. For example, in FIG. 10 , sensor selection cover 1002 mayhave a communication interface 1011, such as a network interface, aWi-Fi™ interface, a cellular network data interface, and/or the like.Smart cover 1002 may have one or more hardware processors, withconnected non-volatile, computer-readable storage medium there attached,and the one or more hardware processors are configured to receive datafrom the sensors, and record the sensor data to the storage medium.Smart cover 1002 may collect sensor data from components under normaloperating conditions. Method 1400 may include a step 1403 of computingnormal operating ranges of sensor values. Method 1400 may include a step1404 simulating component failure, such as by modeling the operation ofthe power device during failure, such as using an electronic designanalysis (EDA) tool, Simulation Program with Integrated Circuit Emphasis(SPICE), and/or the like (Ngspice, LT-spice®, OrCAD®, and/or the like).Method 1400 may include a step 1405 of estimating one or more sensors'data during the failure of the component. Method 1400 may include a step1406 of computing a rule/formula of one or more estimated sensor valuesto detect the failure. Method 1400 may include a step 1407 of selectingdetectors/sensors for the power device design.

The steps of FIGS. 11-14 may be combined to perform alternativetechniques for determining the sensors/rules/formulas for computing aprobability of future failure, as well as performing the computing usingthe sensors/rules/formulas in a power device. For example, the steps ofmethods 1200, 1300, or 1400, may use covers 1002 to determine that sometypes of sensors may not be needed for computing a high probability ofdetermination as in step 1103 of method 1100, but may be candidates forfuture determinations based on a larger sample set, and thus include inthe mass production design implemented in the power device. Duringoperation of the power devices, these low probability sensors may beused to collect data as at steps 1101, 1202, 1205, 1302, and/or 1402,and then the remaining steps of methods 1200, 1300, and/or 1400performed to determine modifications to the rules/formulas as at 1206,1306, and/or 1406. A software and/or firmware update to the power devicemay then incorporate the modifications to perform method 1100 with themodified rules/formulas. For example, a method may use steps of methods1200, 1300, and 1400 to determine the sensors/rules/formulas to use indetecting failures, such as a method 1200 further comprising steps 1304,1305, 1404, and/or 1405 in any combination.

For example, a method for determining the sensors/rules/formulas uses acombination of data collection, simulation, and failure induction. Forexample, a method for determining the sensors/rules/formulas uses acombination of data collection, and failure induction. For example, amethod for determining the sensors/rules/formulas uses a combination ofdata collection, and simulation. For example, a method for determiningthe sensors/rules/formulas uses a combination of simulation, and failureinduction.

For example, film capacitors may incorporate an NTC for failuredetection. For example, an NTC temperature sensor may be used attachedto the PCB, the component, near the component, and/or the like. Aderating mechanism may monitor the highest temperature of a group ofNTCs or one of the NTCs (such as on the side of a DC-AC converter of thepower device that generates heat regardless of the pending failure of acomponent). For example, when the power device is an inverter, theinverter may be derated according to a table determined from laboratorymeasurements of normal operation. The inverter may be derated when anexception to the normal occurs, such as an abnormal heating in a filmcapacitor, especially when such heating happens quickly. As used herein,the term derated means to operate an electronic device at aspecification that is substantially within the specifications of thedevice, such as substantially different than the limits of the deviceoperation. For example, a power device rated to supply 1000 watts ofpower is derated to operate at 800 watts. For example, a refrigeratorthat is rated to reach an internal compartment temperature of −20 deg C.is operated at a temperature of −10 deg C.

One or more processors may be used to monitor sensors and notify of asuspected future failure, such as a pending failure condition. Forexample, one or more processors may be incorporated with or near thesensors for the component(s) to be tested, and the processor(s) used tonotify when the sensors indicate a possible future failure. For example,a processor and sensors may be located near terminals for connectinginput and output power to a device. When the impedance of the terminalsas measured by the sensor(s) and compute by the processor(s) indicates aproblem is eminent, the processor(s) may notify that the performance ofthe power device may be improved and/or fire hazard reduced when theterminals are tightened/reseated.

For example, the sensors may be configured to monitor an attribute ofone or more components by being directed at an orientation to detect achange in the attribute. For example, a sensor may be configured tomonitor the temperature of a component by being configured to detect aninfrared wavelength emission from the component corresponding to thedesired temperature. As used herein, a non-transitory computer-readablestorage medium, such as a memory, hard-disk, flash memory, read-onlymemory, and/or the like, may be connected to the processor to storerules and/or sensor values used to monitor the components pendingfailure condition. When the processor monitors the sensor values, theprocessor continuously collects the sensor values, and evaluates therule with the ongoing sensor values to determine when the rule indicatesthat the component is about to fail.

A sensor may be configured to monitor one component or multiplecomponents. For example, a sensor may be oriented such that severalcomponents are in the field of view of the sensor, and the sensorcomprises a spatial encoding mechanism to separate the attributes ofeach component for evaluation and monitoring, such as an optical camerasensor with an array of sensing elements. The monitoring of theattribute may be a physical attribute, such as a temperature, color,shape, size, and/or the like, or an electrical attribute, such as animpedance, a voltage, a current, and/or the like. When a pending failureis condition is detected, the power device may be derated, such as bymodifying an operational characteristic of the power device, such as acurrent, a voltage, a ramp up/down rate, and/or the like.

A sensor may detect vibration or acoustic attributes of an electricalcomponent by using an acceleration sensor configured to detectvibrations. Similarly, an electromagnetic (EM) radiation sensor may beconfigured to detect electromagnetic radiation interference producedwhen a component is about to fail. A radiofrequency transceiverconnected to the EM sensor and the power of the radio signals used as anindication of pending failure conditions. A chemical sensor, such as agas chromatography sensor, a gas spectroscopy sensor, an ion sensor, anionic sensor, and/or the like may be configured to detect a byproduct ofa pending failure condition, such as gasses produced by the heatedinsulation, hydrogen, methane, and/or the like.

Here, as elsewhere in the specification and claims, ranges can becombined to form larger ranges.

Specific dimensions, specific materials, specific ranges, specificresistivities, specific voltages, specific shapes, and/or other specificproperties and values disclosed herein are example in nature and do notlimit the scope of the present disclosure. The disclosure herein ofparticular values and particular ranges of values for given parametersare not exclusive of other values and ranges of values that may beuseful in one or more of the examples disclosed herein. Moreover, it isenvisioned that any two particular values for a specific parameterstated herein may define the endpoints of a range of values that may besuitable for the given parameter (for example, the disclosure of a firstvalue and a second value for a given parameter can be interpreted asdisclosing that any value between the first and second values could alsobe employed for the given parameter). For example, when Parameter X isexemplified herein to have value A and also exemplified to have value Z,it is envisioned that parameter X may have a range of values from aboutA to about Z. Similarly, it is envisioned that disclosure of two or moreranges of values for a parameter (whether such ranges are nested,overlapping or distinct) subsume all possible combination of ranges forthe value that might be claimed using endpoints of the disclosed ranges.For example, when parameter X is exemplified herein to have values inthe range of 1-10, or 2-9, or 3-8, it is also envisioned that ParameterX may have other ranges of values including 1-9, 1-8, 1-3, 1-2, 2-10,2-8, 2-3, 3-10, and 3-9.

It may be noted that various connections are set forth between elementsherein, elements of both methods and devices. These elements andconnections are described in general and, unless specified otherwise,may be direct or indirect; this specification is not intended to belimiting in this respect, and both direct and indirect connections areenvisioned, nor limiting with respect to combinations of elements. Forexample, the steps of each of FIGS. 11-14 may be rearranged and combinedin any order, and not all steps need be performed. Further, elements ofone feature in any of the embodiments may be combined with elements fromother features in any of the embodiments, in any combinations orsub-combinations. For example, one or more steps of FIG. 11 may becombined with one or more steps of FIGS. 12-14 . For example, skilledreaders of this disclosure may identify method steps that are notdirectly dependent, despite an indication of so in the exemplary methodsdisclosed herein, and reorder the steps differently while achieving thesame result(s) of the disclosed invention.

All described features, and modifications of the described features, areusable in all aspects of the inventions taught herein. Furthermore, allof the features, and all of the modifications of the features, of all ofthe embodiments described herein, are combinable and interchangeablewith one another.

The invention claimed is:
 1. A system comprising: a user terminalcomprising a terminal processor and a graphical user interface (GUI);and a power device comprising: a housing comprising a cover; a printedcircuit board (PCB), wherein the PCB is located inside the housing; atleast one electrical component comprising at least one attribute,wherein the at least one electrical component is located on the PCBinside the housing; at least one sensor configured to monitor the atleast one attribute, wherein the at least one sensor is located on thePCB inside the housing, wherein the at least one attribute is generatedinside the housing; a non-transitory computer-readable storage mediumcomprising at least one alerting rule; and at least one processorconfigured to: retrieve the at least one alerting rule from the storagemedium, monitor at least one sensor value from the at least one sensor,wherein the at least one sensor value is associated with the at leastone attribute, evaluate the at least one alerting rule during themonitoring, and when the at least one alerting rule results in a pendingfailure condition, send a notification to a user by sending thenotification to the user terminal, wherein the terminal processor isconfigured to display the notification on the GUI; wherein the covercomprises a reflector, and wherein the reflector is configured to directthe at least one attribute from the at least one electrical component tothe at least one sensor.
 2. The system of claim 1, further comprisingstoring at least one previous sensor value on the storage medium, andthe at least one previous sensor value is used for evaluating the atleast one alerting rule.
 3. The system of claim 1, wherein the at leastone sensor is configured to separately monitor a plurality of attributesof the at least one electrical component, and the evaluating comprisesanalyzing sensor values associated with the plurality of attributes. 4.The system of claim 1, comprising a plurality of electrical componentscomprising a respective plurality of attributes, and the evaluatingcomprises analyzing sensor values associated with the plurality ofattributes.
 5. The system of claim 1, comprising a plurality of sensors,each sensor measuring at least one of a plurality of attributes, andwherein the evaluating comprises analyzing a plurality of sensor valuesassociated with the plurality of attributes.
 6. The system of claim 1,comprising a plurality of electrical components, and wherein the atleast one sensor is configured to monitor a plurality of attributes ofthe plurality of electrical components, and wherein the evaluatingcomprises analyzing a plurality of sensor values associated with theplurality of attributes.
 7. The system of claim 1, wherein the at leastone attribute is at least one of an electrical property and a physicalproperty.
 8. The system of claim 1, wherein when the at least onealerting rule evaluation indicates the pending failure condition, the atleast one processor modifies at least one operational characteristic ofthe power device.
 9. The system of claim 1, wherein the at least onesensor is located at least 1 centimeter (cm) from the at least oneelectrical component.
 10. The system of claim 1, wherein the at leastone sensor is located at least 2 cm from the at least one electricalcomponent.
 11. The system of claim 1, wherein the at least one sensor islocated at least 5 cm from the at least one electrical component. 12.The system of claim 1, wherein the storage medium is located remotely tothe power device.
 13. The system of claim 1, wherein the at least oneprocessor is located remotely to the power device.
 14. The system ofclaim 1, wherein the cover comprises the at least one sensor.
 15. Thesystem of claim 1, wherein the at least one electrical component isline-of-sight obscured from the at least one sensor.
 16. The system ofclaim 1, wherein the at least one sensor is at last one sensor selectedfrom the group consisting of a temperature sensor, an acoustic sensor, amotion sensor, an acceleration sensor, an optical sensor, a thermalcamera, a digital camera, a photodiode, an infrared photodiode, anelectromagnetic radiation sensor, a magnetic sensor, a radiofrequencytransceiver, a chemical sensor, a gas spectrometer, a chromatographysensor, an ionic sensor, and a humidity sensor.
 17. A method comprising:retrieving at least one alerting rule from a storage medium; directing,using a reflector, at least one attribute of an electrical component ofa power device to at least one sensor of the power device, wherein thepower device comprises a PCB and a housing, wherein the housingcomprises a cover, wherein the electrical component and the at least onesensor are located on the PCB inside the housing, wherein the at leastone attribute is generated inside the housing, wherein the covercomprises the reflector, and wherein the reflector is configured todirect the at least one attribute of the electrical component to the atleast one sensor; monitoring at least one sensor value from the at leastone sensor, wherein the at least one sensor value is associated with atleast one attribute of the electrical component of the power device;evaluating the at least one alerting rule during the monitoring; andwhen the at least one alerting rule results in a pending failurecondition: sending a notification to a user terminal, and displaying thenotification on a graphical user interface of the user terminal.
 18. Themethod of claim 17, wherein the electrical component is line-of-sightobscured from the at least one sensor.
 19. The method of claim 17,further comprising storing at least one previous sensor value on thestorage medium, and the at least one previous sensor value is used forevaluating the at least one alerting rule.
 20. The method of claim 17,wherein the at least one sensor is configured to separately monitor aplurality of attributes of the at least one electrical component, andthe evaluating comprises analyzing sensor values associated with theplurality of attributes.